Psychological interventions for weight reduction and sustained weight reduction in adults with overweight and obesity: a scoping review protocol

Introduction Overweight and obesity are growing public health problems worldwide. Both diet and physical activity have been the primary interventions for weight reduction over the past decade. With increasing rates of overweight and obesity, it is evident that a primary focus on diet and exercise has not resulted in sustained obesity reduction within the global population. There is now a case to explore other weight management strategies, focusing on psychological factors that may underpin overweight and obesity. Psychological therapy interventions are gaining recognition for their effectiveness in addressing underlying emotional factors and promoting weight loss. However, there is a dearth of literature that has mapped the types of psychological interventions and the characteristics of these interventions as a means of achieving weight reduction and sustained weight reduction in adults with overweight or obesity. Methods and analysis The review will combine the methodology outlined by Arksey and O’Malley with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. A total of six databases will be searched using a comprehensive search strategy. Intervention studies will be included if participants are 18 years and over, classified as overweight or obese (body mass index ≥25 kg/m2), and have received a psychological therapy intervention. The review will exclude studies that are not available in English, not full text, none peer reviewed or combine a lifestyle and/or pharmacological intervention with a psychological intervention. Data will be synthesised using a narrative synthesis approach. Ethics and dissemination Ethical approval is not required to conduct this scoping review. The findings will be disseminated through journal publication(s), social media and a lay summary for key stakeholders.

Authors need to add an appropriate sub-heading to convey this important message to the readers, users -programme managers and researchers, etc.
Study limitations and strengths: A brief statement on these might be useful to the readers.

REVIEWER
Lukes, Sophie University Medical Center of the Johannes Gutenberg University Mainz, Department of Child and Adolescent Psychiatry and Psychotherapy REVIEW RETURNED 01-Aug-2023

GENERAL COMMENTS
Thank you for the opportunity to review " Psychological interventions for weight reduction and sustained weight reduction in adults with overweight and obesity: a scoping review protocol.",whose topic is both interesting and highly relevant.
Following, you'll find some recommendations and concerns: Choice of review method: Please state more clearly why you choose to do a scoping review instead of a systematic review.You mention in the part on strengths and limitations that the review offers to determine gaps in evidence, yet, I think that it would be beneficial not only to name and describe current interventions, but also to see if they have a positive impact on weight loss.This is well written.In addition, "wholly effective…" need to be explained or phrased in a way to give a common understanding of ineffectiveness of some PA & diet-related interventions.
In a similar manner to the abstract, we have re-phrased 'wholly effective' to state that dietary and physical activity interventions have not resulted in a sustained obesity reduction within the global population (see page 3).Lines 33-36: I have not seen the authors mention stress as an important psychological factor.
We have added stress as an important factor within line 33, and also highlighted stress within the second paragraph of the introduction (see page 3).Aim and objectives: This is excellently crafted.However, I have will suggest that the authors merge objectives 3 and 5 together, as these are focusing on almost the same outcome/outputs.
Thank you for the feedback.We are hesitant to merge these two objectives as objective 3 refers specifically to the identification of study characteristics of 'psychological interventions', and objective 5 refers to the identification of core characteristics of 'usual care'.Methods and Analysis: This is well-ordered.
What is the expected outcome and use of this study?It will be of importance to science, to be able to know what exactly the findings of this study (and or its methodology) would add to the body of literature and to science, that might be different from what the many systematics and meta-analysis on obesity interventions have added so far.How would the results be useful to programme implementers, WHO, INGOs, local NGOs, academia, etc? Authors need to add an appropriate sub-heading to convey this important message to the readers, usersprogramme managers and researchers, etc.
We have included a section on 'what the findings may add' towards the end of the methods and analysis section, as suggested.'We have stated that the scoping review is likely to identify specific gaps within existing evidence that may be useful in shaping future research initiatives.The identification of these gaps could pave the way for the development of novel innovative psychological interventions and may provide a roadmap for researchers to explore the effectiveness for these interventions.The findings may also assist healthcare providers and key public health organisations gain insight into the types of psychological interventions that can be utilised as a means of weight reduction and sustained weight reduction for adults with overweight and obesity.With a greater understanding of psychological interventions (i.e., the types, characteristics and impact) for weight reduction and sustaining weight reduction, key organisations and healthcare services can tailor programs to include evidenced based psychological components' (see page 8).
Study limitations and strengths: A brief statement on these might be useful to the readers.
We have included a 'strengths and limitations' section with bullet points to highlight these to the reader (see page 2), as per the BMJ protocol submission guidance.

Reviewer 2
Choice of review method: Please state more clearly why you choose to do a scoping review instead of a systematic review.
We have added a further paragraph on page 5 which states why we choose to do a scoping review: 'A scoping review design was chosen because it enables an exploration of the broader spectrum of evidence relating to range of psychological therapy interventions for adults with overweight and obesity, without being constrained by a rigid inclusion and exclusion criteria of a systematic review.Given the absence of previous reviews which have explored the objectives of this study, the scoping review methodology allows for a more expansive inclusion criteria (e.g., different study designs and intervention types) which will ensure that all relevant studies will be included.The scoping review design has been found to be well-suited for topics that are rapidly evolving and include a heterogeneous body of literature, which is applicable to psychological interventions as a means for achieving weight reduction and sustained weight reduction'.You mention in the part on strengths and limitations that the review offers to determine gaps in evidence, yet, I think that it would be beneficial not only to name and describe current interventions, but also to see if they have a positive impact on weight loss.
Thank you for the comment, we value the suggestion and agree an effectiveness analysis would be beneficial.That said, we do not plan to include an analysis of effectiveness as this would be more appropriate for a full systematic review rather than a scoping review.However, we fullybecause we intend to conduct a full systematic review (with meta-analysis) to establish the effectiveness of these interventions once we have the findings from this scoping review.This scoping review will, by its nature, give us a clearer insight into the research available in this area, and will inform the parameters required for a full systematic review.We feel it is important not to miss out this vital step.Additionally, the resources we currently have available for this project do not allow us to conduct the full SR at this time.We are unable to conduct an analysis of effectiveness in this scoping review&#a0;because the project is restricted by time and funding, hence why we have only proposed the scoping element in this protocol.
Included studies: Do you include studies from a specific period or shall all existing studies on interventions be included?
We have clarified in the search strategy that there will no limiters related to year of publication (see page 5).Literature: In the introduction, you name reference 7 (Kyrou I, Christou A, Panagiotakos D, Stefanaki C, Skenderi K, Katsana K, et al.Effects of a hops (Humulus lupulus L.) dry extract supplement on selfreported depression, anxiety and stress levels in apparently healthy young adults: a randomized, placebocontrolled, double-blind, crossover pilot study.Hormones (Athens).2017;16(2):171-80.) as evidence, that obesity increases the risks for comorbidities, yet, for me, this reference does not seem to be fitting, because, although information on weight is gathered in this study, it focuses on depression and anxiety

GENERAL COMMENTS
Thank you for the revised edition of this interesting manuscript.All my previous aspects and questions were sufficiently answered and revised.I have just one small last recommendation for the introduction: I would recommend to restructure the sentence "While these factors are critical for weight loss, they ignore the complex psychological (e.g., fears), emotional (e.g., stress), and behavioural factors (e.g., avoidance) that underpin overweight and obesity (6,(15)(16)(17)(18)." to "While these factors are critical for weight loss, they ignore the complex psychological factors (e.g., emotional, such as fears and behavioural, such as avoidance) that underpin overweight and obesity (6,(15)(16)(17)(18)." since both emotional and behavioural factors are psychological factors and this sentence structure could be potentially misunderstanding to some readers.Thank you.

VERSION 2 -AUTHOR RESPONSE
Thank for the feedback.We have re-upload the supplementary file in PDF format and have restructured the sentence as per reviewer two's suggestion: I would recommend to restructure the sentence 'While these factors are critical for weight loss, they ignore the complex psychological (e.g., fears), emotional (e.g., stress), and behavioural factors (e.g., avoidance) that underpin overweight and obesity (6,(15)(16)(17)(18).' to 'While these factors are critical for weight loss, they ignore the complex psychological factors (e.g., emotional, such as fears and behavioural, such as avoidance) that underpin overweight and obesity (6,(15)(16)(17)(18).'